Eliminate sending NOTIFICATION_TOP_SITES_* from TopSites

components/history/core/browser/top_sites_observer.h

+// Copyright 2014 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef COMPONENTS_HISTORY_CORE_BROWSER_TOP_SITES_OBSERVER_H_
+#define COMPONENTS_HISTORY_CORE_BROWSER_TOP_SITES_OBSERVER_H_
+
+namespace history {
+class TopSites;
+
+// Interface for observing notifications from TopSites.
+class TopSitesObserver {
+ public:
+  // Is called when TopSites finishes loading.
+  virtual void TopSitesLoaded(history::TopSites* top_sites) = 0;
+
+  // Is called when either one of the most visited urls
+  // changed, or one of the images changes.
+  virtual void TopSitesChanged(history::TopSites* top_sites) = 0;
+};
+
+}  // namespace history
+
+#endif  // COMPONENTS_HISTORY_CORE_BROWSER_TOP_SITES_OBSERVER_H_